Hi! i was just wondering.. i've been having really painful headaches. but they get even worse in the far, bottom left part of my head. i had cancer when i was 12, and it was blood cancer. i'm worried, but don't wanna seem like a hypochondriac?

Try the Chicago Diamond Headache clinic who will empirically diagnose the issue and come up with evidence based treatments.

Location may raise question of occipital neuralgia, but would also consider migraine. I would be extremely skeptical of any relationship of prior "blood cancer". You could start with your primary care doctor, or get a virtual consult here at HT (www.connect@healthtap.com).